Long-Term Oxygen Therapy Can Improve Survival in Patients With Oxygen-Dependent COPD
Surabhi Dangi-Garimella, PhD
Patients with severe alpha-1 antitrypsin deficiency (AATD) are at an increased risk of developing chronic obstructive pulmonary disease (COPD). Now, a new study has shown that long-term oxygen therapy (LTOT) in this patient population can improve survival; however, their outcomes do not improve following lung-transplantation.
Found in 1% to 2% of patients with COPD, the PiZZ phenotype, which is characteristic of AATD, is a significant cause for COPD. Along with vaccinations, bronchodilators, rehabilitation, and surgical interventions in selected patients, LTOT is also a treatment option.
In the current study, published in the International Journal of COPD, 14,644 patients who were on LTOT due to their COPD were enrolled. Patients with AATD, the authors note, tended to be younger, male, and never smokers. The study used data from the Swedish National Registry for Respiratory Failure for the period between January 1, 1987, and June 30, 2015.
At a median follow-up of 1.6 years on LTOT, patients without severe AATD had higher mortality (hazard ratio [HR] 1.53; 95% CI, 1.24–1.88)—there were 201 (71%) deaths among patients with AATD and 12,354 (86%) deaths among patients without AATD. The median survival was 1.9 years (95% CI, 1.8–1.9) overall; patients with AATD had a significantly longer survival (3.5 years; 95% CI, 2.8–4.3) than patients without AATD (1.9 years; 95% CI, 1.8–1.9; P<.001). This was after normalizing for age, gender, smoking status, body mass index, performance status, level of hypoxemia, and comorbidities. Cardiovascular deaths were higher in patients without AATD (16% compared with 6%; P<.001).
Of the 171 patients who underwent a lung transplant during the follow-up period, 53 (31%) had severe AATD. At a 4.4 year median follow-up after a lung transplant, 103 patients died, 36 (35%) of whom had severe AATD. While a higher proportion of AATD patients had a lung transplant—19%, compared with 1% of those without AATD—survival was similar for both populations. Higher age, according to the authors, was the only significant predictor of death after a lung transplant in this population.
Based on their findings, the authors conclude that patients with severe AATD have better survival in oxygen-dependent COPD, but prognosis following a lung transplant is independent of their AATD status.
Ekstrom M, Tanash H. Lung transplantation and survival outcomes in patients with oxygen-dependent COPD with regard to their alpha-1 antitrypsin deficiency status. Int J COPD. 2017;12: 3281-3287.